SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd33d5d2f5f527aa3bb5eee5c1bfadbadb886c8fd571142d0c5f3665030e3aeed' 
  AND token = 'TrCtYku/cB5evGzi6X3XcJ7XvJAi1GvnVYtFZCxZm5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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