SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf2dbfb555ae8ef957072654cb4d5bead24ae51dd45756c201c242fe39c5ab51' 
  AND token = 'CaIji/Q2CUgEVLOXOQgISLEPAeEUYeWO5V5f3s+Tya8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}