SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b985523d535ad015d959ebfba252ff270c479770788497cae580a2a4ea389150' 
  AND token = 'Jqqx7TnG9GFthwAO9VxT2kjbuMIYYWHPRSNb+z20nA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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