SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2e85a42343339668e6aa091f105aad8b815358cea0cf8b9d64c9ede13fddd9c' 
  AND token = 'vlNpDCRxA5pGB7zNZjVmmwo1GEYAklN/gjE56pkKbqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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