SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '749347cfdebaebb53e23e6855812dc98285ac2ae42a65baea5b0e55c71c711b7' 
  AND token = '7YL4pEnHE1u92pwlDpnpQPtGFSRHSxHCmvntu53IDt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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