SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7bad19b5ec3aeda3dfb4e80f820570b0f878ac8ebf2221c1ab836bf80035f56' 
  AND token = 'WEFIH9EAaaLmdTl3pT2YxFk2uyQp7j6Y+OuZ24oiQCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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