SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0811c3bcb64e6144f0c90dd00a9196a645c2c1317719bf9c0fecd14f4675f27c' 
  AND token = 'LlRdgRIjyEtDyYfe1BK4XqzBXSeoOVq9fhyYfzzoXEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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