SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8702881e61c1ee1438c0d92b411cf7d7b1234ae9a930a113be5b44918be5174' 
  AND token = '8Vv+SXSzXAv6GRmZX+WsFYMCfaGlgOPjxlwho/TdDQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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