SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8ddd553e84baa8543c5d37eb591b180aabf1bfc1a438962c2d09e3f71911932' 
  AND token = 'RDp0ecrNtl0qqkjYjHRJwQ7Mkm2B/hW5KU/D1j5WPug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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