SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84efa56a0d1144d60528458700cf3d2e50431dda0e795500a94c2177867851a' 
  AND token = 'CNks5PlHAOK0W0AgyPFI3oP5cTWU55O5dh1785Amb9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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