SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddbc52f323645bf3d2d7904639b8895958f672b7eb98f3acecd5c6b4fcde2f91' 
  AND token = 'zALxp99IhTRVupOSFWDjNgktUjSA1Jt3uOsAXUSxAZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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