SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c425e81b1bb9f8977815f6bc932b7b2a2056781f8576b54e8338b073595cb639' 
  AND token = 'm7JRttdNEGK1mqB89tLvIV9GuQpcRcvVZLftqGRUkYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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