SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb547a82d7dbf77f49bea2119e6ffb28753b0bfc5144d97be009b0af068c5d2e' 
  AND token = 'DMRfx77j0oPT7cVxoPAGqFJFSDuOeRrSaVjIkkWMZf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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