SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '275569363d58b7d968fda327a5618adb4f5e93e9abbc456382639f8e115767fd' 
  AND token = 'cj+yQ6+oRupDWZ0qhuibGQ/H+Tq/1Rcdo+V2us/hEn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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