SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b74691a773517f5d0740a5fbd8ec60aaf165d590a6b04664c328232700e9ec' 
  AND token = 'GAPLJNvA2zq74ABVQxM1RF7HDZg2bg0iXgmTJ9vC3KY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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