SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '295e1ce60d6ce9565563dc9a981ddce74d40d0cbce6113b159d153e1a12819d7' 
  AND token = 'F62bgcMHQx1QTEOp8f2qOVLZju6tHuWAt16l1ZUIuR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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