SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce57f0aa5c5c7aa7d66640d54be385447a341a88b55becdf7c1553e750a35863' 
  AND token = 'ckhxRWn1PwLaMJ52VhOWZzIJsY29PPd4SArXogvqRMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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