SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37f2f0b956e457d8bc2695b9f6e06c2643e4827d4863a20c1b7d4c755ff6e98d' 
  AND token = 'tDa17oj+w6Vp69eGzNguRJupRWcc2IKyGsRBYhFfkDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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