SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2e363fd236d42ec2546c50ba39d51c4483bb8d96ca41d99c61268b4f4396818' 
  AND token = '1M+QGTyyd5CxISkjh97t03NAyuT0STYwNQ8+95hhOiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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