SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d433cbe16ca2254c45a08d680b2c8c107268ea0a5704a1f593c1e9a610fef6b' 
  AND token = '3hk5WT4wgjm5ZnogVfshPlVIx6dDORFRLuEwZe11pXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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