SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9151d3d6537409c626667136d18f2e03ed6696edb15d122318132e66408fd8c' 
  AND token = 'q+cqAtIXR3h8MrrdwNtbeSETKqqJ0rKNhd61CBxQQys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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