SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '446ce525450e6e427aefad122b3efd3ebdbf904fd4981414c0b17fe0cf2807f2' 
  AND token = 'J8hYvfEuOnTXhzmtvA92rSXBikcnd9fcBchOFJru+Ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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