SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '428eb25c74edd1844f090e592a3d455b1a31e4544ebd792d7ea19a82a5d9f376' 
  AND token = 'EbCdtlbA8KZo/EBPVzojE9rLwfbHKKJPrPtR3Ic+4P8=' 
  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"
    }
  }
}