SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1a1c56c598e81bc2d6421f64866483a8bfd70a38aac8c29557910bb91363f54' 
  AND token = 'TGapfMtDWtuZ7gpGdz1d/SSude61nphcux0kPmMDM/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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