SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6988ca3f1ebd64ad110543a0192e42e26650ab8787ece18810ca4f7bb130d436' 
  AND token = 'dZ2FKG4sLPzjDev0lPnfDzmpK/CrjuBn1n97btv2S60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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