SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cedd208c8f676b5d52ead02252568dc2bec06d99fff59a8ae58a56ee5a331e89' 
  AND token = 'OY2oRpT+o6j7Q6UET2JWDcCneCA8OXIhKlSTpSWyk7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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