SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6be6697f8c027b42396f4d80574bfd72c59ba195d6c43656f8508370d5443427' 
  AND token = 'Q2wtZl7XHVsc2nvd7RQ67EB2gbLULuS3JGKg9iEPr4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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