SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67019fea79c1931ddaeb03e6f1dfae6e5b034930162d9978401e44a4ee78550e' 
  AND token = '7UsqIVCiVCfUjpYH+mFGDYC1UL2DXmIMzLHYZUrFquM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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