SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12a1a314bed002216a8b6de52e50e3f95b984ecbfe9d575d0c357622b4df0e01' 
  AND token = 'hV9OzUC2aOV8XFVQMISk3XRJS2AKrz177CTLYW/MoSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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