SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6950fc1bddfc037a962e0854a7eca1abce2ef42f6be25e14b12d2f162e02ee5e' 
  AND token = 'JwNC+I/mPuulJyAF7pgMoCChMqwLdhoQvRzGjVjmdxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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