SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cdcf665ce144ee77732972f814fec3d690965f387076792fd8eda054f0e37a5' 
  AND token = 'HbsBpL5TAaXLbSHiOnPLNzUdVpoAqCZWsh2ZSoo6wVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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