SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a42b7fba2af2a0e436552080487818e2d65873cf1f65f9ceecb18d756411e163' 
  AND token = 'eArxAQgflvhfkj9zzqVCuTyk2GYu4PKp/reNISw+5fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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