SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c75e0060950e20c2dd0b0ebd4721d0d5c524a2300e991d2bd02f55d6a98d1a30' 
  AND token = 'PmnpNVCRv2n2ZYI4Tp+wGu3iSbpvXcGOTreAgU2N6iQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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