SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96fdc25669bc7a333645cbd991825289964e50169594c18cc94ab7006f893fbd' 
  AND token = 'XwzTjxYKFQ5HOLBLkfYmDtZ8Pfu6tm/vyRpy9MA4/hk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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