SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2eba6bc4a25e5dd58e3efafe7a8afdcbc06d2a03bc5b343c09add2b038353afd' 
  AND token = 'CsaTJf7rENNqBxrUWbO+jXamwvEGlM2sxVG1rALpEKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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