SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15dde0b2b816acf4480edc45e0f036c5d99e5e917473ff8eb69127e221104e83' 
  AND token = 'bNrmCN0d2l1O7nC1aqUCuRqtWKEHfhR8OjoHmRUoJM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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