SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '427ee3386ec6bbe23eebc3c98f818614476ece66663f2be725549f70d5b31041' 
  AND token = 'yBxf3TBNIAlemmUbHzK9SfYkLyDrnWieu7ZOk6kVx7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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