SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4551f4a7352b19d575b4623bb6431409d30caee50491569e5acd29234cc05249' 
  AND token = 'qXLUIS/Dt7lM7ze6rV2Atfdfa0lqtZv/SRDh88wAkSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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