SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2c7d1c99978ea49031b06a05ef15470511377f570b2f5ed658b54cf81899b5a' 
  AND token = 'V6L3US1FvdoxKZ2bmN69eY+lSFPqgYqez/j2K4a9lM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}