SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea9bd052823af9aea1690a2d642acf759d1f8efa029dccd905da6a7d520f631a' 
  AND token = 'yleKkqZAgBnEq85sU7Y8uCHezxPc1YWP/JKqndqZFhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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