SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2ca7472cf341b563e740f5dbfb45029bc8d2b231d4b7505051bb73dd1486ebf' 
  AND token = '3Ce6psv7XpWFHIY6iZ9Ld+JpYtxqE8s3nc/HdPTU2no=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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