SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe0b4d0cec59cdced590913d01f722a2e239f75fd3d747a1c9ab53504f4be88a' 
  AND token = 'MIDOboU0Qiym+RFqeo4/V/nYSqHMDJ9bIUvO3iqJXpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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