SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a1361986bc78d1a9a3df156bce8b0b50c7d947da3a9b8b60267c8273b32bdb2' 
  AND token = 'MbrmgKhVsPncIue1JX6hwbzp4ZT2BYGuk5PthWlkqRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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