SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd5171fa646603ce3965ff0385d56fdc9028e6de2c52f88b30765a97e66a9142' 
  AND token = 'LqdncoR+1da7Wzq1/7+L+DTMh9IN8H3IL5hqLXkOfz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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