SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee28129b6bb982c5acb508e9e363cdc5e55f16766fb11daecb3fa35e5047a1ad' 
  AND token = 'OSLFpoxRXgTAf9rO9eYbl2RGb87LZS2/JleKoxz7U74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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