SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f74fca9bdbac56e70d6635cea25b06755dce286cfeed0909c75ed64523c09470' 
  AND token = '38vpZmkxBFvqSmvFLuayCFxqs1cnwBgBdywt65pcKeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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