SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29d10b6d1f12a420bfd7afb591255f11758c54549fd0ae17f9a8cd4e6235167c' 
  AND token = 'qC+BoGVIpZ3pb6aMUYRdqQETLU38Cjbyb+mIdsozP2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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