SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc86edf70957c7db1bda9ccffb44aeaf403445ebccc66066a471fbeb583c29b5' 
  AND token = 'FDOe52hPS/26mHu9zQ78MftyJ98aRuetTvkqFtu2FYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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