SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7d174a9afc100cd768c553585cb5e77af42277daa59ed39864e9fb341738e5e' 
  AND token = 'T9BJyCTqmbmwPDHpoZSMjbwSLJLsURWf3p45KoVJWJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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