SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d872e6ce52391df3397cc08634fa861fbb9bbe0ded1d90e0063a057653817fc' 
  AND token = 'mRMJZSNeDkTRkPfp4FjPvugP45AMK95QbJ8VJZX/kZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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