SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c756f0683599c36108f78daa8137559ab640c29b8a177b14612df6ccb6561f86' 
  AND token = 'RnCZXOTSHFPGrdzVcB2YIp/SfTc9tXV3t9IRKe43vmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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