SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fc79a3f2eededc3a0c38eaa0865cd94ed0483733076129e3937733758246256' 
  AND token = 'FzFOSC5HBkZ7w2cFiZYfgDoWMzdSLgvv6CzSmzxpijw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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