SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7a0c94705740dcb68080ad994af6b9cd9fecbf40516835eb97d1db4751eb80' 
  AND token = 'V2rfxkxTDGZHKrV0giz893UK4rSzUdb3VgW6EBk/mkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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