SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3cb0e4056aaeeceb794a5b4d8224e38cea758469296afec13088e4ac6ebc15d' 
  AND token = 'brVUexoFEskZXZmeZazqqKlXXVEV+VOURMP/I1sR10Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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