SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45846f09f7690ea832a42007f9eeae764fcedb534a17c6ecb3898131c47dab97' 
  AND token = 'CSxgEPDFPuhGGYzNcjkfCMhQWcDqMSuV3J2qw8BFZeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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