SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4692834ec48ee6fb262e14ed3286408bc3f6c8b0014e41196cf2f475c126c8' 
  AND token = 'IZlWcXNE8yxc1yiII0Yiw+Q6uftojzCRqE1yihlxfSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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