SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7fec29416e4dc58d0c1ec9d76e07d5e9ee61ae53f0a05034f23502b7240e993' 
  AND token = 'y6Qt9qSTPLJvuRrLJ5iaGF+/uJblAksy3MPgsjeqPYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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