SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aaf69b305a406601db16c2b9bbe16984c67add5fa4972e710802b9067fdccab' 
  AND token = 'zAOpV9tsUiPhc4ElKjs97ijJJGPT1SeAZKdZFOdwdzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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