SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b1b4faf02a812ff4d4ab37f00b5663e0d0921961b65d5dbe8a2f952562c7e4' 
  AND token = 'DACLAOaEU28Y7vD6P8TQM7adHcC/2Q9PjzwzM+JKQD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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