SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f40e4fc13bab24d8299710cf3ed59edffb3bf1c5e30fd812aabf249cfc26e8fe' 
  AND token = '2oKtudrDibJtduCmRg0mvCuWlRsOhuUANXCWLulOO3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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