SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48559b6737f497f4516b7ee03359fcff9fcd0b46791d7da698b03af5168bb538' 
  AND token = 'wo786B1fdPXi1QkJnX1DM+BFYTMQdJggYQ5BgGtl1As=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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