SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66eb13200eb82f08271a72a9c3bd8995dd2340dce58c4db1d79a5c07652f252a' 
  AND token = '5TCjC4avo65U7ZFQE0HOucwfRMkwPFYn46fQlMfDYD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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